Replacing screen time, with physical activity and sleep time: influence on cardiovascular indicators and inflammatory markers in Brazilian children

Abstract Objective: To examine if the substitution of different screen time intervals with light physical activity (LPA), moderate to vigorous physical activity (MVPA) and sleep is associated with cardiovascular indicators and inflammatory markers in children. Methods: This is a cross-sectional study developed with 186 children aged between six and 11 years old from public schools in southern Brazil. CRF was measured with the 6-minute running and walking test, following the Brazil Sports Project procedures. The percentage of fat was evaluated through DXA. LPA and MVPA were measured using accelerometers. Sleep and screen time were assessed by questionnaires answered by parents. Leptin and C-reactive protein were measured by fasting blood collection. Systolic and diastolic blood pressure were determined through a digital sphygmomanometer. Isotemporal substitution models were used for statistical analysis. Results: Replacing 1 h of screen time with MVPA was associated with lower BMI, systolic and diastolic blood pressure, fat percentage, leptin, and C-reactive protein. When screen time was substituted for sleep time, lower waist circumference was observed. Regarding the substitution of 1 h of screen time with LPA, significant values were found only for leptin. Conclusion: The replacement of screen time with physical activities of different intensities and sleep time was associated with benefits in cardiovascular indicators and inflammatory markers in childhood.

Replacing screen time, with physical activity and sleep time: influence on cardiovascular indicators and inflammatory markers in Brazilian children.

OBJECTIVE: To examine if the substitution of different screen time intervals with light physical activity (LPA), moderate to vigorous physical activity (MVPA) and sleep is associated with cardiovascular indicators and inflammatory markers in children. METHODS: This is a cross-sectional study developed with 186 children aged between six and 11 years old from public schools in southern Brazil. CRF was measured with the 6-minute running and walking test, following the Brazil Sports Project procedures. The percentage of fat was evaluated through DXA. LPA and MVPA were measured using accelerometers. Sleep and screen time were assessed by questionnaires answered by parents. Leptin and C-reactive protein were measured by fasting blood collection. Systolic and diastolic blood pressure were determined through a digital sphygmomanometer. Isotemporal substitution models were used for statistical analysis. RESULTS: Replacing 1 h of screen time with MVPA was associated with lower BMI, systolic and diastolic blood pressure, fat percentage, leptin, and C-reactive protein. When screen time was substituted for sleep time, lower waist circumference was observed. Regarding the substitution of 1 h of screen time with LPA, significant values were found only for leptin. CONCLUSION: The replacement of screen time with physical activities of different intensities and sleep time was associated with benefits in cardiovascular indicators and inflammatory markers in childhood.

Prevalence and sociodemographic correlates of physical activity and sitting time among South American adolescents: a harmonized analysis of nationally representative cross-sectional surveys.

BACKGROUND: To identify the prevalence and sociodemographic correlates of different domains of physical activity (PA) and higher sitting time among South American adolescents. METHODS: Data from national surveys of 11 South American countries were analyzed, and comprised information on 166,901 adolescents. PA (≥ 60 min/day of moderate-vigorous PA), physical education classes (PEC) (≥ 3 classes/wk), active commuting to school (≥ 1 d/wk), and higher sitting time (≥ 3 h/d) were self-reported. Sociodemographic correlates, such as gender, age, and food security status were explored using a random effect meta-analysis for logistic parameters. RESULTS: Recommended PA ranged between 7.5% (Brazil) and 19.0% (Suriname). Peru (2.2%) and Guyana (43.1%) presented the lowest prevalence of PEC and active commuting to school, respectively. Higher sitting time was less prevalent in Bolivia (24.6%) and more prevalent in Argentina (55.6%). Compared to girls, boys were more prone to reach recommendations for PA [OR = 1.94(1.65;2.28)]; to reach ≥ 3 PEC [OR = 1.17(1.04;1.33)] and to be active in commuting to school [(OR = 1.14(1.06;1.23)], but less prone to higher sitting time [OR = 0.89(0.82;0.96)]. Older adolescents had less odds of reach PA guidelines [OR = 0.86(0.77; 0.97)] and accumulated higher sitting time [OR = 1.27(1.14;1.41)]. Adolescents with food insecurity reported more PEC [OR = 1.12(1.04;1.21)] and active commuting to school [OR = 1.12(1.02;1.22)] but had less higher sitting time than their food security pairs [OR = 0.89(0.81;0.98)]. CONCLUSIONS: Few adolescents reach the PA recommendation. Actions aiming the promotion of PA and the reduction of sitting time must consider girls and older adolescents as target groups, as well as the specifics of each country.

Movement behaviors in short versus adequate nocturnal sleepers: A compositional analysis of preschoolers.

BACKGROUND: Accruing adequate daily amounts of time spent on movement behaviors (physical activity (PA), sedentary behavior (SB), and sleep) in childhood has been associated with positive short and long-term health outcomes. Nonetheless, how waking time is distributed across PA and SB among preschoolers who are short and adequate sleepers at night is unknown. AIM: This study investigated: (1) if there are differences in a movement behaviors composition among adequate and short nocturnal sleepers; and (2) the association between preschoolers' time spent in PA, SB, and sleep among adequate and short nocturnal sleepers. METHODS: A total of 270 preschoolers (132 boys; 3.97 ± 0.81 years old; 15.48 ± 1.62 kg/m2 ) participated in this study. PA and SB were assessed using accelerometry (model wGT3X). Sleep duration was assessed through a parental-proxy interview, and preschoolers were stratified as short and adequate sleepers, according to attendance to international sleep duration guidelines. Compositional data analysis was used to explore the time-use patterns of behaviors among adequate and short sleepers. RESULTS: Short sleepers spent 64 min less time asleep, accumulated 32 min in more sedentary time (p = .005, Cohen's d = 0.36, Bayes Factor: 6.17), and 24 min more in light PA (p = .0005, Cohen's d = 0.44, Bayes Factor: 46.37) compared to adequate sleepers. CONCLUSIONS: Being a short sleeper was associated with greater time spent in SB and light PA during their waking hours. The health implications of movement behaviors composition among short sleep preschoolers should be further investigated.

Exercise in school Physical Education increase bone mineral content and density: Systematic review and meta-analysis.

ABSTRACTThis systematic review and meta-analysis aimed to evaluate the effectiveness of interventions through Physical Education (PE) exercises on bone mineral content (BMC) and density (BMD) of children and adolescents. The research was conducted using the online electronic databases PubMed, Science Direct, Web of Science and Scopus (March 2021). The analysis was restricted to school-based studies that examined the effect of PE interventions on BMC and BMD in schoolchildren (<18 years old). Standardised mean differences (SMD) with 95% confidence interval (CI) and random-effects models were calculated. The heterogeneity and inconsistency of the studies were estimated using Cochran's Q-statistic and I2, respectively. Twenty-two studies with 2,556 participants were selected. PE interventions were associated with a significant increase in BMC (SMD = 1.348; 95% CI, 1.053-1.643) and BMD (SMD = 0.640; 95% CI, 0.417-0.862). Femoral neck subgroup analysis indicate an increase in BMC for boys (SMD = 1.527; 95% CI, 0.990-2.065) and girls (SMD = 1.27; 95% CI, 0.782-1.767), and in BMD for boys (SMD = 0.518; 95% CI, 0.064-0.972) and girls (SMD = 0.817; 95% CI, 0.349-1.284). Finally, increases are reported in the lumbar spine BMC for boys (SMD = 1.860; 95% CI, 1.018-2.700) and girls (SMD = 1.275; 95% CI, 0.782-1.767). This meta-analysis provides insights into the effectiveness of interventions aimed at including physical exercise in PE on bone mass, suggesting that increasing the proportion of curriculum time allocated to PE may improve students' BMD and BMC, especially in the femoral neck and lumbar spine.

Associations between Movement Behaviours and Obesity Markers among Preschoolers Compliant and Non-Compliant with Sleep Duration: A Latent Profile Analysis.

This study identifies physical activity (PA) and sedentary behaviour (SB) clusters in preschoolers compliant (C) or non-compliant (NC) with sleep recommendations; and associates these clusters with obesity markers. PA and SB were objectively assessed (Actigraph WGT3-X) in 272 preschoolers (4.4 ± 0.7 years old). Sleep duration was parent-reported, and preschoolers were classified as C (3-4 years old: 600-780 min/day; 5 years old: 540-660 min/day) or NC with sleep recommendations. Body mass index (BMI) and waist circumference (WC) were assessed according to international protocols. Moderate to vigorous physical activity (MVPA) and light physical activity (LPA) were categorized as low/high (<60 min/>60 min/day or <180 min/180 min/day, respectively). SB was defined according to mean values between clusters. Latent profile analysis was performed. Associations between the observed clusters and obesity markers were determined using linear regression (RStudio; 1.3.1073). Four cluster solutions for C and NC preschoolers were identified. A negative association between C/Low MVPA cluster and BMI, and a positive association between NC/Low MVPA and BMI (ß = -0.8, 95%CI = -1.6;-0.1, and ß = 0.9, 95%CI = 0.1;1.7, respectively) were observed. No association was seen for SB clusters. Adequate sleep duration may have a protective role for preschoolers' BMI, even if the children do not comply with MVPA recommendations.

Higher Physical Activity Is Related to Lower Neck Adiposity in Young Men, but to Higher Neck Adiposity in Young Women: An Exploratory Study.

The role of lifestyle behaviors on neck adipose tissue (NAT), a fat depot that appears to be involved in the pathogenesis of different cardiometabolic diseases and in inflammatory status, is unknown. In this cross-sectional and exploratory study, the authors examined the relationship between sedentary time and physical activity (PA) with neck adiposity in young adults. A total of 134 subjects (69% women, 23 ± 2 years) were enrolled. The time spent in sedentary behavior and PA of different intensity were objectively measured for 7 consecutive days (24 hr/day), using a wrist (nondominant)-worn accelerometer. The NAT volume was assessed using computed tomography, and the compartmental (subcutaneous, intermuscular, and perivertebral) and total NAT volumes were determined at the level of vertebra C5. Anthropometric indicators and body composition (by dual-energy X-ray absorptiometry) were determined. The time spent in light physical activity and moderate physical activity (MPA) and the overall PA were inversely associated with the intermuscular NAT volume in men, as were the MPA and overall PA with total NAT volume (all ps ≤ .04). Sedentary time was directly related to the total NAT volume (p = .04). An opposite trend was observed in women, finding a direct relationship of MPA with the subcutaneous NAT; of light physical activity, MPA, and overall PA with the perivertebral NAT; and of light physical activity with total NAT volumes (all ps ≤ .05). The observed associations were weak, and after adjusting for multiplicity, the results became nonsignificant (p > .05). These findings suggest that the specific characteristics of PA (time and intensity) might have sex-dependent implications in the accumulation of NAT.

Physical fitness profile in elite beach handball players of different age categories.

BACKGROUND: The aims of this study were to compare anthropometric and fitness variables of high-level beach handball players across Under-19 (U-19), Under-21 (U-21) and senior male categories, and between male and female senior players; and to test the correlations among those measures. METHODS: A total of 70 high-level players (53 male of different ages) were evaluated for 5-m acceleration, 15-m sprint, horizontal jump, handgrip strength, specific beach handball throwing velocities, and anthropometric variables. Differences between age groups were tested using ANOVA. Independent t-test was used to compare fitness variables between male and female elite athletes, and Pearson partial correlation coefficients were calculated between each of the fitness variables using BMI and age as covariates. SPSS Software was used, and the level of significance was set at 95%. RESULTS: The U-21 athletes better performed on horizontal jump and 6-m throw than the U-19 athletes. Senior athletes showed better performance on horizontal jump than U-19 athletes (P≤0.05). Positive correlation was seen for handgrip on dominant and non-dominant hands and 6-m throwing speed, and for handgrip on dominant hand and inflight velocity (P≤0.05). Negative correlations were observed between horizontal jump and 5-m acceleration, and 15-m sprint (P≤0.01 and P≤0.05, respectively). CONCLUSIONS: Male athletes better performed than women in all the fitness tests. The study, for the first time, showed physical fitness comparisons between beach handball elite male athletes of different ages and between genders. These are key steps for coaches and athletes and may support future beach handball studies and practice.

Is motor competence associated with the risk of central obesity in preschoolers?

OBJECTIVES: To investigate the association between motor competence (MC) and central obesity in preschool children. METHODS: The sample comprised of 472 children aged 3 to 5 years (4.58 ± 0.70 years, 248 boys) from Recife, Brazil. MC was assessed using the Test of Gross Motor Development-2. Waist-to-height ratio (WHtR) was calculated and a cutoff of 0.5 was used to define central obesity. Logistic regression was used to examine the association between MC and WHtR ≥ 0.5. RESULTS: The prevalence of central obesity (WHtR) was 54.0% and 46.4% for boys and girls, respectively. Older children (OR = 0.61; CI = 0.44-0.84; P < .01) and those with higher MC in locomotor skills (OR = 0.96; CI = 0.93-0.99; P < .01) were less likely to present WHtR ≥ 0.5. Sex and object control skills were not associated with WHtR ≥ 0.5. CONCLUSIONS: To reduce the risks of central obesity in children, health practitioners should focus on increasing competence in locomotor skills since preschool years.